Resource Link

[tobywf]

Issue #, if available: #62

Description of changes: Allow resource authors to attach template links to the schema that consumers of the schema/resources can use to generate links directly to the resource. An example might be EC2. The console link is:

https://eu-central-1.console.aws.amazon.com/ec2/home?region=eu-central-1#Instances:instanceId=i-xxxxxx

In this case, the service link might look like this:

"serviceLink": {
    "templateUri": "/ec2/home?region=${awsRegion}#Instances:instanceId=${instanceId}",
    "mappings": {
        "instanceId": "/InstanceId"
    }
},

Where awsRegion is a "global" variable (so far, the only one), and instanceId is a variable defined via a JSON pointer to a property in a resource blob (returned by e.g. READ) and not in the schema. The relative URI is debatable, but works well for the console currently. Other users outside of the console would have to maintain a mapping of console endpoints by region. The other benefit is that it lets us clearly figure out which links are AWS-internal.

For non-AWS services, an absolute, HTTPS URI can be used.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[rjlohan]

Do we need this section? We can only pre-fill fields from the schema anyway, could the tokens in the URL just be the json-pointers directly?

[tobywf]

we did consider this, but this way it might be possible to use existing templating engines, or simple regex replace. might be good for the console team to create a PoC to see how difficult/easy both would be.

[rjlohan]

Fair enough.

[PatMyron]

AWS::DAX::ParameterGroup is a good candidate for a proof-of-concept:

/dynamodb/home#cache-parameter-group:selected=${lowercasedResourceId}

[benkehoe]

Does this support other partitions, like China? Additionally, what if there is more than one kind of link that a provider wants to define?

[tobywf]

Yes, partitions are not an issue for AWS links as they have to be relative. For external links, they can go off the region. If there's really a need for the partition, we can add that as a global variable later.

1:1 seems to make sense to keep things simple. I don't think we're keen on displaying multiple links in the stack resources tab either, could lead to a confusing UX. I'm also not aware of any use-cases for multiple links. And while that's a somewhat weak argument as people do build cool stuff with extensible systems, predicting use-cases is hard and I'm leaning towards simplicity.

[tobywf]

Happy with the state of this and think it's ready for inclusion!

[PatMyron]

only concerns are the discoverability of how mappings works and things like ${awsRegion} if more get supported, but we can improve that while adding more